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Re: [ddlm-group] Focusing the elide discussion
- To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
- Subject: Re: [ddlm-group] Focusing the elide discussion
- From: Brian McMahon <bm@iucr.org>
- Date: Tue, 18 Jan 2011 12:05:09 +0000
- In-Reply-To: <AANLkTinUHwGQOYo6dafhKSb0Pv9gKbNMZhZ27bvb_Ha8@mail.gmail.com>
- References: <AANLkTinUHwGQOYo6dafhKSb0Pv9gKbNMZhZ27bvb_Ha8@mail.gmail.com>
Dear James Sorry for the delay in replying to this request. A long train journey yesterday gave me the opportunity to review the discussions on this point. In order of preference I would rank the proposals as roughly: F' - requires least handling of special escapes E - allows the generic handling of Unicode character set and long lines as native CIF2 features (but only within "special" i.e. triple-quote delimited strings) I think these allow embedding of any string in a reasonably clean way. C - I quite like, provided the post-elide escape could be a sequence (e.g. borrowing from TeX, the trigraph "{} is read as a double-quote; the literal sequence <doublequote><open brace><close brace> would be represented by "{}{} and any other sequence would have no special meaning). If those with greater experience argue that this imposes too great a load on the initial lexical scan, or can demonstrate that this leads too quickly to a proliferation of unreadable punctuation marks, this would drop quickly down the lilst of preferred approaches). F - because I'm not sure what is gained just by protecting the escape character everywhere; but on the other hand it may seem an easy procedure to describe to potential implementors A B - carries an unwelcome overhead in requiring the escape character (here, backslash) to be encoded everywhere D P - brings in unnecessary syntactiv overhead when we can achieve a closed system by simpler means. Best wishes Brian On Thu, Jan 13, 2011 at 12:20:09AM +1100, James Hester wrote: > By my count there are 6 distinct proposals for eliding triple-quoted > strings on the table, which I have listed below. In order to get an > idea of where we all stand and which proposals are most likely to > succeed, I'd like to invite you all to reply to this email with a list > of proposals which you would find acceptable. If you like, you can > rank them in order of preference. In the list below I've given short > descriptions, but you should refer to the original emails for the full > details. The opinions of COMCIFS voting members are of course most > significant at this juncture, but I for one am interested in the > thoughts of the other members as well. > > Proposal P (for Python): Ralf's original proposal to do everything as in Python > Proposal A: <backslash><delimiter> elides the delimiter, no other > sequences are significant > Proposal B: \uxxxx to represent Unicode characters, no other sequences > are significant > Proposal C: as yet unspecified character post-elides the delimiter > where necessary > Proposal D: as for C, except post-elide character is given immediately > before opening triple delimiter > Proposal E: (John B's suggestion) \uxxxx for Unicode character > together with \<newline> and \\ > Proposal F: (Simon's proposal) \<newline> and \\ only > Proposal F': (My slight tweak of Simon's proposal) \<newline> only > when not preceded by \ > > I find proposal P unacceptable, and would rank the others in order of > preference roughly as follows: > > Best: F', F, C > Bearable: A, B, E > In a pinch: D > > -- > T +61 (02) 9717 9907 > F +61 (02) 9717 3145 > M +61 (04) 0249 4148 > _______________________________________________ > ddlm-group mailing list > ddlm-group@iucr.org > http://scripts.iucr.org/mailman/listinfo/ddlm-group _______________________________________________ ddlm-group mailing list ddlm-group@iucr.org http://scripts.iucr.org/mailman/listinfo/ddlm-group
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